To prepare the garlic & herb sauce, mix the entire packet with 1 1/2 cups of milk and one tablespoon of butter and bring to a boil in a small pot. Cook for 3 minutes whisking continually. Reduce the heat to a simmer and keep warm while you prepare the rest of the ingredients.
Steam the green beans per the instructions on the package, slightly undercooking, or cook in salted water until crisp tender. [around 4-5 minutes] Drain well.
Set the green beans aside while you prepare the mushrooms.
In the same pot, heat 2-3 tablespoons of olive oil then add the minced shallot. Cook until the shallot becomes translucent then add the mushrooms.
Season with salt and pepper and cook the mushrooms on medium high heat for 5-6 minutes or, until they begin to caramelize and brown.
Increase the heat slightly, then pour the red wine vinegar over the mushrooms.
Add one tablespoon of butter and the partially cooked green beans to the mushrooms.
Saute everything together on medium-high heat until the green beans are heated through and tender. [around 4-5 minutes] Taste and adjust the seasonings if needed.
To serve, arrange the sauteed green beans and mushrooms on a serving platter, drizzle with the garlic & herb cream sauce then sprinkle with garlic-pepper onions. Serve hot.